This article explains what XCF files are, how to open them, and how to convert them to another format.
How to Open Gimp XCF File in Photoshop | Convert XCF File to PSD
A file with the file extension XCF, which stands for eXperimental Computing Facility, is a GIMP image file.
Similar to PSD files used in Adobe Photoshop, GIMP uses XCF files to store layers, transparency settings, paths, and other information associated with one or more photos that are part of the same project.
When you open the file in a compatible image editing program, all the settings will be accessible again, allowing you to edit the layers, images, etc.
